How does electronegativity change within a period from left to right?

As you move from left to right across a period in the periodic table, electronegativity increases. This trend can be attributed to the increase in the effective nuclear charge experienced by the electrons in the valence shell. As more positively charged protons are added to the nucleus while the shielding effect remains relatively constant, the ability of the nucleus to attract bonding electrons also increases.

For example, elements on the left side of the periodic table, like sodium or magnesium, have a lower electronegativity because they have fewer protons attracting the valence electrons. In contrast, elements on the right, like fluorine and chlorine, have a much higher electronegativity due to their higher number of protons, which results in a stronger attraction for electrons.

This increasing electronegativity across a period is crucial for understanding chemical bonding and the nature of interactions between different elements, as more electronegative atoms are more likely to attract electrons towards themselves in a bond.